Refractory metal phosphates have long been recognized as useful building and insulating materials. Compositions comprising phosphoric acid, a metal oxide and metal silicates are known in the art; however, compositions comprising these constituents and having adequate strength and acoustic properties are extremely difficult to prepare. For example, mixtures of aluminum oxide and 85% phosphoric acid are viscous and difficult to handle. If such mixtures are diluted With water, the ease of handling is greatly improved; however, when silicate, e.g. calcium silicate, is added and the resulting phosphate is thermally cured to drive off excess water, the refractory material obtained has relatively poor tensile strength and its acoustic properties are also poor.